In order to elucidate the interrelationship between pulmonary emphysema and chronic bronchitis, 23 adult patients with chronic obstructive pulmonary disease were examined during life by selective alveolo-bronchography. They were classified according to radiologic criteria as centrilobular or panlobular emphysema or chronic bronchitis and according to clinical criteria as A, B or X types. A and B clinical types proposed by Burrows and Fletcher were almost in agreement respectively with emphysema and chronic bronchitis based on x-ray criteria. However, no correlation between A-type and panlobular emphysema or between B-type and centrilobular emphysema were observed. Centrilobular emphysema was diagnosed in 4 patients who had no history of findings of bronchitis. This suggests that inflammation of airways is not necessarily a cause of centrilobular emphysema. As a result, selective alveolo-bronchography was thought to be useful method to diagnose the type and severity of emphysema.